If these incidents are repeated and they happen frequently, it could have a more serious effect on the president's popularity and credibility.
And if they can increase the rate of abstention by scaring people away from voting, that would rob Uribe of some of his electoral legitimacy.
In practice he has been able to reduce crime statistics, like kidnapping and homicide, in the major cities.
The paramilitaries played a decisive role in this election, particularly in the northern part of the country.